A cancer genetics-tracking database will be redesigned using usability engineering techniques to improve the functionality and usability of the current system. This is important because it will lead to a system that is easier to use and learn, will decrease the chance of errors, and will increase productivity, and user satisfaction. The current state of informatics offers the potential for the creation of tools to assist in the reduction of medical errors. The redesign of this tracking database will be completed through a three-phase process. The first phase will use the results of a usability analysis to redesign and prototype the cancer genetics-tracking database. In the second phase, usability studies will then be conducted to ensure that the system is functional, easy to use, easy to learn, and meets the goals of the users. The usability studies will include heuristic evaluations, keystroke level models, talk-aloud methods, and cognitive walkthrough techniques. The system will be modified based upon the results of these studies. Research will be compiled on the advantages and disadvantages of ICD coding Vs. SNOMED followed by the selection of the most useful system for coding medical information. In the third phase the final redesign will be compared to the old system using a within-subject design to determine if the redesign decreases the error rate, increases productivity, and user satisfaction. This will be followed-up with a survey to determine the perceived usability of the redesigned application. Throughout the redesign process, specific usability guidelines will be developed for designing healthcare software that is computational and knowledge- based in nature.